Identifying patterns behind the changes in skin pores using 3-dimensional measurements and K-means clustering.

BACKGROUND: Skin pores are structural features of the skin, which tend to change as the skin ages. Since previous studies measured pores two-dimensionally, precise measurements using three-dimensional imaging were needed to comprehensively understand skin pores. This study aimed to determine the patterns behind the changes in skin pores during one's lifetime and to identify new characteristics of the pores in aged. MATERIALS AND METHODS: Skin surface profiles were measured three-dimensionally from the cheeks of 101 Korean women from February to March 2020 to analyze the exact state of their pores. The researchers performed K-means clustering to classify the skin pores, and topographical features of pores were analyzed as well. Statistical analyses were performed to verify the differences in the skin pore characteristics among clusters and the correlation between clusters and ages. RESULTS: Skin pores were classified into five groups based on size, density, and elongation. The skin conditions of the cluster groups were well correlated with aging, despite excluding age as a factor in pore classification. Adjacent skin pores tend to connect in the elderly. CONCLUSION: Skin pores become larger and longer over time. Skin pores connect together in the elderly, which might be related to wrinkle formation. This phenomenon strongly suggests skin pores as a characteristic of aging skin and as a potential target for anti-aging treatment.

Influence of quarantine mask use on skin characteristics: One of the changes in our life caused by the COVID-19 pandemic.

BACKGROUND: The influence of various environmental factors on skin properties is well known. However, there is a lack of research into the effect of quarantine masks on skin properties, even though the use of masks has significantly increased after the COVID-19 outbreak. Therefore, this study aimed to investigate the influence of mask use on skin properties. MATERIALS AND METHODS: Twenty subjects were enrolled in this study. The subjects used approved quarantine masks for 6 hours a day for 2 weeks. We measured eight skin biophysical parameters: temperature, redness, pore volume, texture, elasticity, trans-epidermal water loss (TEWL), sebum content, and pH, and evaluated acne lesions before and after using quarantine masks. The evaluation was performed on the mask-wearing area of the face. RESULTS: Skin temperature, redness, and TEWL increased significantly after a 6-hour mask use, while the sebum content increased marginally. Skin elasticity was reduced by the use of masks over 1 and 2 weeks, whereas the pore volume and the number of acne lesions increased after a 2-week mask use. The skin changes caused by mask use showed sex-based differences in the skin elasticity (after 6 hours), redness, and roughness (after 2 weeks). CONCLUSIONS: The use of quarantine masks causes a change in the skin temperature, redness, and TEWL in the short term and in skin elasticity, pores, and acne in the long term. This study revealed that prolonged mask use could have negative effects on the skin.

Validation of the elastic angle for quantitative and visible evaluation of skin elasticity in vivo.

BACKGROUND: Reduction in skin elasticity due to aging causes skin sagging and wrinkles. Although there are various objective and reliable techniques for measuring skin elasticity, it is difficult to obtain a visual representation of skin elasticity with them. Therefore, we developed a novel device, the Swing anglemeter, and analyzed its effectiveness for measuring skin elasticity of the cheek. MATERIALS AND METHODS: Forty-five healthy Korean women (age, 23-60 years) participated. The Swing anglemeter works by dropping a rubber ball on a subject's cheek, which draws a curve as it collides with the cheek. After recording the movement of the ball using the slow-motion function on a mobile phone, we defined the maximum angle at which the ball bounces off the skin as the elastic angle, using frame-by-frame video analysis. Changes in the elastic angle were assessed according to age, and correlation with the Ballistometer® results (Dia-stron Ltd., Andover, UK) was analyzed for validation. RESULTS: Elastic angles differed significantly (P < .001) according to age. A negative correlation was found between the elastic angle and age (r = -.799, P < .001). Compared with the Ballistometer® measurements, the elastic angle was negatively correlated with alpha (r = -.570, P < .001); it was positively correlated with the mean coefficient of restitution and area (r = .602, P < .001 and r = .535, P < .001, respectively). CONCLUSION: The elastic angle is a useful parameter for reflecting skin elasticity, both quantitatively and visually. Our method can help subjects understand their skin elasticity status. Therefore, we expect the device will be utilized in various fields within the cosmetic industry.

Comparative analysis of skin characteristics evaluation by a dermatologist and the Janus-III measurement system.

BACKGROUND: The Janus-III measurement system evaluates the overall skin characteristics such as skin pore, wrinkle, sebum, porphyrin, skin pigmentation, and skin color using high-resolution facial images. The values are measured from five different facial areas, namely, the forehead, nose, corner of/skin below the eyes, and cheeks. Owing to its convenience and diverse measuring characteristics, Janus-III has been widely used in skin research and the cosmetic industry in Korea. In our previous study, we revealed the consistency and reliability of the system with repeatedly measured values. Its measuring performance was investigated statistically, but to make it more reliable for academic skin research, additional verification by a professional dermatologist is needed. MATERIALS AND METHODS: In this study, we conducted comparative analysis of three skin characteristics (pigmented spot, skin color, and eye wrinkle) by a dermatologist and the Janus-III measurement system. We utilized 330 image data that were cropped from the whole facial images of 330 different participants to avoid correlation among the three measuring items. Pearson's correlation coefficient exhibited similar patterns between the system and the dermatologist's findings. RESULTS: The main finding of our study was that the measured value of skin characteristics by the Janus-III system showed clear correlation with the values evaluated by a dermatologist, especially in a pigmented spot. CONCLUSION: Therefore, it would be a plausible idea to consider the Janus-III system for specialized research of skin characteristics even with a small sample size.

Relationship between lip skin biophysical and biochemical characteristics with corneocyte unevenness ratio as a new parameter to assess the severity of lip scaling.

OBJECTIVE: Lip skin dryness and chapping are major concerns related to lip skin care in many populations. The distinctive features of lip skin, such as the low water-holding capacity and weak skin barrier, are strongly associated with these problems; however, few studies have examined lip skin characteristics and the mechanisms underlying these issues. This study was conducted to identify the biophysical properties of dry lip skin and molecular targets affecting lip skin physiology. METHODS: Skin hydration, transepidermal water loss and lip skin scaling were evaluated in 40 female subjects. Skin scaling was assessed as a percentage area divided into five categories (G0, G1, G2, G3 and G4) according to the thickness level of tape-stripped corneocytes. The activities and amounts of proteases, cathepsin D and bleomycin hydrolase were measured as markers for the desquamation process and skin hydration, respectively. RESULTS: Skin hydration showed a significantly positive correlation with the percentage area of evenly thin corneocytes (G0) and negative correlations with the percentage areas of slightly thick to severely thick corneocytes (G1-G4). The corneocyte unevenness ratio (CUR) was calculated by dividing the sum of the G1, G2, G3 and G4 values with the G0 value. The CUR was significantly negatively correlated with skin hydration, suggesting that CUR is a new parameter representing the severity of lip scaling. Subjects with lower hydration and higher CUR had higher bleomycin hydrolase activity and lower cathepsin D activity, respectively, than subjects with higher hydration and lower CUR. CONCLUSION: Our study revealed a correlation between lip skin hydration and severity of lip scaling and verified the association of protease activity with the hydration and chapping state of lip skin. These observations provide a basis for further studies of the persistent problem of lip skin dryness and chapping.

OBJECTIF: La sécheresse et la gerçure de la peau des lèvres sont des préoccupations majeures liées aux soins de la peau des lèvres chez de nombreuses populations. Les caractéristiques distinctives de la peau des lèvres, telles que la faible capacité de rétention d'eau et la faible barrière cutanée, sont fortement associées à ces problèmes ; cependant, peu d'études ont examiné les caractéristiques de la peau des lèvres et les mécanismes sous-jacents à ces problèmes. Cette étude a été menée dans le but d'identifier les propriétés biophysiques de la peau sèche des lèvres et les cibles moléculaires affectant la physiologie de la peau des lèvres. MÉTHODES: L'hydratation cutanée, la perte d'eau transépidermique et la desquamation de la peau des lèvres ont été évaluées chez 40 sujets de sexe féminin. La desquamation cutanée a été évaluée en tant que pourcentage de surface, divisée en cinq catégories (G0, G1, G2, G3 et G4) en fonction du niveau d'épaisseur des cornocytes sur la bande adhésive. Les activités et quantités des protéases, de la cathepsine D et de la bléomycine hydrolase ont été mesurées comme marqueurs du processus de desquamation et de l'hydratation cutanée, respectivement. RÉSULTATS: L'hydratation cutanée a montré une corrélation significativement positive avec le pourcentage de surface avec cornocytes uniformément minces (G0), et des corrélations négatives avec les pourcentages de surface avec cornocytes légèrement épais à très épais (G1-G4). Le rapport d'irrégularité des cornocytes (Corneocyte Unevenness Ratio, CUR) a été calculé en divisant la somme des valeurs de G1, G2, G3 et G4 par la valeur de G0. Le CUR était significativement corrélé négativement avec l'hydratation de la peau, ce qui suggère que le CUR est un nouveau paramètre représentant la gravité de la desquamation des lèvres. Les sujets avec une hydratation plus faible et un CUR plus élevé présentaient une activité de la bléomycine hydrolase plus élevée et une activité de la cathepsine D plus faible, respectivement, par rapport aux sujets avec une hydratation plus élevée et un CUR plus faible. CONCLUSION: Notre étude a révélé une corrélation entre l'hydratation de la peau des lèvres et la gravité de la desquamation des lèvres, et a vérifié l'association de l'activité de la protéase avec l'état d'hydratation et de gerçure de la peau des lèvres. Ces observations fournissent une base pour d'autres études sur le problème persistant de la sécheresse et de la gerçure de la peau des lèvres.

Relationship of transcutaneous oxygen tension with age and skin elasticity in Korean women.

BACKGROUND: Oxygen has several positive effects on the skin, including improving collagen synthesis and accelerating wound healing. However, only a few studies have investigated the relationship between skin oxygenation and skin aging parameters. Therefore, this study aimed to assess the correlation between skin oxygenation and skin aging parameters-elasticity, hydration, sebum, color (lightness, redness), and blood perfusion-in Korean women. MATERIALS AND METHODS: We evaluated the transcutaneous partial pressure of oxygen, also known as transcutaneous oxygen tension (TcPO2 ), and skin aging parameters, including elasticity, hydration, sebum, color (lightness or redness), and blood perfusion, in the cheek of 34 healthy women (aged 20-69 years) and assessed the correlation between TcPO2 and other skin aging parameters using IBM SPSS Statistics 25 software (SPSS Inc). RESULTS: Facial TcPO2 was negatively correlated with age (P < .05). There were positive correlations between facial TcPO2 and elasticity parameters (P < .01). We noted no correlation between facial TcPO2 and skin lightness; however, skin lightness tended to slightly improve with increasing TcPO2 . Skin aging parameters, including hydration, sebum, skin redness, and blood perfusion, showed no correlations with TcPO2 . CONCLUSION: In Korean women, facial TcPO2 tends to decrease with increasing age and is positively correlated with gross, net, and biological skin elasticity. Therefore, this study demonstrated that oxygen tension of facial skin can be a major causative factor of skin aging.

Repeated measurements of facial skin characteristics using the Janus-â ¢ measurement system.

BACKGROUND: For personalized skin care, noninvasive quantitative methods to evaluate facial skin characteristics are important. Janus-III is one of the most widely used imaging analysis devices in the skin care industry in Korea. Janus-III generates values for a range of skin characteristics. Due to the convenience of obtaining results for a variety of skin characteristics in a single measurement, the use of Janus-III in cosmetic stores and research institutes has been recently increasing. However, the consistency of skin measurements of Janus-III has not been elucidated yet. MATERIALS AND METHODS: In this study, we repeated skin measurements three times for 70 different subjects and compared each numerical value in order to assess the consistency of the Janus-III. For this purpose, we compared between-sample distances and within-sample distances. RESULTS: We found important patterns for future analyses in terms of consistency. First, the average values of skin measurement categories were more reliable than individual part values of facial segments. Second, center part values such as forehead and nose were more reliable than side part values such as left and right part segments. CONCLUSION: If researchers who use Janus-III for studies of facial characteristics analyze average and center part values first, they can obtain relatively reliable patterns of facial skin characteristics.

Machine learning for the prediction of sunscreen sun protection factor and protection grade of UVA.

We report a prediction model for sunscreen sun protection factor (SPF) and protection grade of ultraviolet (UV) A (PA) based on machine learning. We illustrate with real clinical test results of UV protection ability of sunscreen for SPF and PA. With approximately 2200 individual clinical results for both SPF and PA level detection, individually, we were able to see that active ingredient information can provide accurate SPF and PA prediction rates through machine learning. Furthermore, we included four new factors-presence of pigment, concentration of pigment grade titanium dioxide, type of formulation and type of product-as additional information for the prediction model and were able to see increased prediction rates as results.

Mapping and annotating genomic loci to prioritize genes and implicate distinct polygenic adaptations for skin color.

Evidence for adaptation of human skin color to regional ultraviolet radiation suggests shared and distinct genetic variants across populations. However, skin color evolution and genetics in East Asians are understudied. We quantified skin color in 48,433 East Asians using image analysis and identified associated genetic variants and potential causal genes for skin color as well as their polygenic interplay with sun exposure. This genome-wide association study (GWAS) identified 12 known and 11 previously unreported loci and SNP-based heritability was 23-24%. Potential causal genes were determined through the identification of nonsynonymous variants, colocalization with gene expression in skin tissues, and expression levels in melanocytes. Genomic loci associated with pigmentation in East Asians substantially diverged from European populations, and we detected signatures of polygenic adaptation. This large GWAS for objectively quantified skin color in an East Asian population improves understanding of the genetic architecture and polygenic adaptation of skin color and prioritizes potential causal genes.

Enhancement of Efficacy of Retinoids through Enhancing Retinoid-Induced RAR Activity and Inhibiting Hydroxylation of Retinoic Acid, and Its Clinical Efficacy on Photo-Aging.

Retinoids, one of the most robust bioactive materials, have been widely used to improve various dermatological and pathological conditions. The body has an endogenous mechanism that modulates the exogenous retinoid above physiological concentrations, which limits the bioavailability or pharmacological efficacy of retinoids. Considering that most retinoids trigger extensive irritation in users, it is necessary to enhance the pharmacological efficacy of retinoids, thereby achieving a higher efficacy at a lower dosage. Here, we present approaches for enhancing the efficacy of retinol by enhancing retinoid-induced RAR gamma (RAR-γ) activity and inhibiting the hydroxylation of retinoic acid. Using both in vitro and ex vivo experiments, retinoid boosters were demonstrated to enhance pharmacological efficacy. A small pilot study was conducted to investigate the efficacy for improvement of facial wrinkles, whose results revealed that these boosters could enhance the pharmacological efficacy of topical applications of both retinol and retinoic acid for cosmetic use. These results promote not only a higher compliance among retinoids users, but also provide significant insights into the mechanisms underlying the action of retinoids.

Sugar-Triggered Burst Drug Releasing Poly-Lactic Acid (PLA) Microneedles and Its Fabrication Based on Solvent-Casting Approach.

Microneedles have emerged as a novel transdermal delivery tool that enables the delivery of various products such as drugs, vaccines, or cosmetic ingredients. Although the demand for solid microneedles composed of biocompatible polymer is increasing, the manufacture of microneedles using poly-lactic acid (PLA) with rapid drug-releasing is yet to be established and the process is still in its infancy. Here, we propose a novel strategy for the fabrication of PLA solid microneedles which enable a drug to be burst-released based on a solvent-casting process. This approach offers extreme simplicity, broad geometric capability, cost-effectiveness, and scalability based on high fidelity-replicas. It was verified that microneedles of various heights (250-500 µm) could be fabricated with appropriate mechanical strength to penetrate the stratum corneum layer of skin. By adding sugar in the composition of PLA microneedle, it was observed that both hydrophilic and hydrophobic drugs can be rapidly released within 30 min. Our burst drug-releasing PLA microneedle having both characteristics of solid microneedle and soluble microneedle and its fabrication approach based on solvent-casting will contribute to getting microneedle technology close to commercialization and beyond existing technical limitations.

GWAS Identifies Multiple Genetic Loci for Skin Color in Korean Women.

Human skin color is largely determined by genetic factors. Recent GWASs have reported several genetic variants associated with skin color, mostly in European and African populations. In this study, we performed GWAS in 17,019 Korean women to identify genetic variants associated with facial skin color, quantitatively measured as CIELAB color index. We identified variants in three, one, and six genomic loci associated with facial skin color index L∗, a∗, and b∗ values, respectively, and replicated the associations (combined analysis P-value < 5.0 × 10-8). The significant loci included variants in known genes (OCA2 rs74653330, BNC2 rs16935073, rs72620727 near KITLG, and SLC6A17 rs6689641) and to our knowledge previously unreported genes (SCARB1 rs10846744, SYN2 rs12629034, and LINC00486 rs6543678). This is GWAS to elucidate genetic variants of facial skin color in a Korean female population. Further functional characterizations of the investigated genes are warranted to elucidate their contribution to skin pigmentation-related traits.

Novel human skin surface antimicrobial peptide quantification method using a skin patch test chamber: A pilot study.

INTRODUCTION: Antimicrobial peptides (AMPs) on the skin surface are related to the innate immunity of the skin in preventing external infection. Skin rinsing and tape stripping (TS) are acceptable methods for analyzing AMPs on the skin surface but have limitations, such as causing skin damage. In this study, we proposed a noninvasive method to measure AMPs on the skin surface with minimal skin damage. METHODS: Using the patch test assay, we aimed to analyze the skin surface human ß-defensin (hBDs) levels without damaging the skin barrier. The concentrations of hBDs on the skin surface were evaluated through the skin patch testing of 13 healthy subjects, and hBD-1 concentrations were compared with those obtained using the TS method in this proof-of-concept study. In addition, changes in skin physiology and concentration of hBDs under 1% sodium lauryl sulfate stimulation were monitored in 14 healthy subjects (8 young and 6 elderly subjects) for 150 h. RESULTS: The correlation between the two methods had a Pearson's coefficient of 0.640, and skin patch analysis led to a relatively less impaired barrier with no significant increase in transepidermal water loss after analysis. Age-specific comparisons suggested that higher skin surface hBD-2 concentrations were present in the young group as compared with the elderly group. Skin surface expression of hBD-2 after skin barrier disruption was also higher in the young group. CONCLUSION: Our findings show that skin patch analysis is a convenient method to analyze hBDs on the skin surface. hBDs are factors of innate immunity that can be used as an index to predict a decreased chemical immune response of skin due to aging.

The effect of intraperitoneal ropivacaine on pain after laparoscopic colectomy: a prospective randomized controlled trial.

BACKGROUND: Although laparoscopic procedures are becoming more common, postoperative pain remains a major factor causing delayed patient recovery. There have been several trials to reduce pain by instilling local anesthetics into the peritoneal cavity, but there has been no study on prolonged (∼300 min) or intensive surgery. We investigated the analgesic effect of intraperitoneal ropivacaine instillation after laparoscopic colectomy. MATERIALS AND METHODS: Sixty patients were randomized to three groups. Twenty patients in each group received 50 mL of appropriate solutions after the formation of a pneumoperitoneum. The solution was normal saline (control) in group C and 1 mg/kg of ropivacaine in each of groups I and D. In group D, ropivacaine was sprayed again before the elimination of the pneumoperitoneum. Patients reported their postoperative pain using a subjective visual analogue scale. Fentanyl use for pain relief and frequency of pushing a button (FPB) for a bolus of patient controlled analgesia were evaluated, and scales of recovery rates were obtained. RESULTS: The immediate postoperative pain score was lower in groups I and D than in group C. In groups I and D, FPB measures and fentanyl use were both less than in group C. The time taken to resume a regular diet was shorter in group D than in group C. CONCLUSIONS: The intraperitoneal instillation of ropivacaine was effective in reducing postoperative pain and in shortening the recovery course after laparoscopic colectomy. The additional instillation of ropivacaine at the end of the surgery proved even more effective.

Less perilaryngeal gas leakage with SLIPA™ than with LMA-ProSeal™ in paralyzed patients.

PURPOSE: The aim of this study was to compare the Streamlined Liner of the Pharynx Airway (SLIPA™) with the ProSeal Laryngeal Mask Airway (LMA-ProSeal™) in mechanically ventilated paralyzed patients undergoing laparoscopic gynecologic surgery. METHODS: One hundred and one patients were allocated randomly to SLIPA (n = 50) or to LMA-ProSeal (n = 51) treatment groups. After induction of general anesthesia and insertion of the assigned supralaryngeal airway (SLA) device, we made note of the occurrence of any gastric insufflation and perilaryngeal leakage. We then evaluated the anatomical fit of the SLA device using a fibreoptic bronchoscope, and we assessed the airway sealing pressure and respiratory mechanics with change in head position and during peritoneal insufflation. After surgery, we evaluated the severity of postoperative sore throat and the presence of blood or regurgitated fluid on the SLA device. RESULTS: The insertion success rate, gastric insufflation, perilaryngeal leakage, anatomical fit, airway sealing pressure, respiratory mechanics, severity of sore throat, and incidence of blood and regurgitated fluid on the device were similar between the two groups. The incidence of perilaryngeal leakage with changes in the patient's head position was lower with the SLIPA group than with the LMA-ProSeal group (3/50 vs 11/51, respectively; P = 0.026). During peritoneal insufflation, perilaryngeal leakage did not occur with the SLIPA but occurred in four cases with the LMA-ProSeal (P = 0.045). CONCLUSION: Both the SLIPA and the LMA-ProSeal can be used effectively and without severe complications in paralyzed patients undergoing laparoscopic gynecological surgery. However, the SLIPA offers the advantage of less perilaryngeal gas leakage than the LMA-ProSeal with change in head position and during insufflation of the peritoneal cavity. This trial is registered with ANZCTR (ACTRN12609000914268).

Development of the facial glycation imaging system for in situ human face skin glycation index measurement.

BACKGROUND: The accumulation of advanced glycation end products has been proposed as a causative agent of skin aging, but there are no conventional devices for quantifying advanced glycation end-product accumulation in facial skin. AIMS: This study aimed to develop a convenient and accurate in situ advanced glycation end-product measurement system for the human face. METHODS: We developed a facial glycation imaging system, which consisted of illumination (white light-emitting diode, ultraviolet light-emitting diode) and image acquisition modules to capture face images. Advanced glycation end product-related autofluorescence and total skin reflectance were calculated to obtain the skin glycation index using an image analysis algorithm. Correlations between the skin glycation index and facial skin elasticity and age were examined in 36 healthy Korean women. RESULTS: The facial glycation imaging system was validated against a volar forearm skin autofluorescence measurement device, that is, the AGE Reader mu, with forearm skin glycation index (R = 0.64, P < .01). Cheek elasticity was negatively correlated with cheek skin glycation index (R = -0.56, R = -0.57, and R = -0.61, P < .01 for R2, R5, and R7, respectively). Age was significantly correlated with forearm skin glycation index (R = 0.44, P < .01) and cheek skin glycation index (R = 0.48, P < .01). CONCLUSION: We successfully developed a novel in situ facial skin glycation index measurement device. Our convenient and accurate system enables in situ skin glycation index monitoring for skin aging studies such as those on anti-glycation cosmetics.

Biophysical characteristics of dandruff-affected scalp categorized on the basis of sebum levels.

BACKGROUND: Various sebum levels can be detected in dandruff-affected scalps. However, few studies have compared the biophysical characteristics of dandruff scalps categorized based on sebum levels. AIMS: To investigate and compare the biophysical characteristics of dandruff-affected scalps categorized based on sebum levels. METHODS: Fifty-four Korean women with dandruff and 30 healthy Korean women underwent physiological measurements, including evaluation of sebum and hydration levels, pH, and transepidermal water loss (TEWL) in the scalp. The levels of the biomarkers of interleukin-8 (IL-8) and kallikrein 5 (KLK5) and corneodesmosomes were investigated in the stratum corneum (SC) of the scalp. RESULTS: Dandruff was categorized as dry (low-sebum, n = 25) or oily (high-sebum, n = 29) based on a sebum cutoff level of 97.82 µg/cm2 . Both dry and oily dandruff-affected scalps showed significantly decreased hydration levels and increased pH and TEWL compared with healthy subjects, with hydration levels being lower in dry dandruff-affected scalps. IL-8 expression was significantly increased in the oily dandruff-affected scalp. In addition, both dry and oily dandruff-affected scalps showed significantly increased KLK5 levels in the SC, with the levels being higher in oily dandruff-affected scalps. Altered distribution of corneodesmosomes, present on the entire surface area of the corneocytes, was notable in oily dandruff-affected scalps. CONCLUSION: The biophysical characteristics of the two types of dandruff represent the influence of different characteristics, including hydration levels, expression of IL-8 and KLK5, and corneodesmosome distribution. Thus, strategies to reduce dandruff levels should differ according to sebum levels.

Effect of the skincare product on facial skin microbial structure and biophysical parameters: A pilot study.

Daily use of cosmetics is known to affect the skin microbiome. This study aimed to determine the bacterial community structure and skin biophysical parameters following the daily application of a skincare product on the face. Twenty-five Korean women, who used the same skincare product for four weeks participated in the study. During this period, skin hydration, texture, sebum content, and pH were measured, and skin swab samples were collected on the cheeks. The microbiota was analyzed using the MiSeq system. Through these experiments, bacterial diversity in facial skin increased and the microbial community changed after four weeks of skincare product application. The relative abundance of Cutibacterium and Staphylococcus increased, significant changes in specific bacterial modules of the skin microbial network were observed, and skin hydration and texture improved. It was suggested that daily use of skincare products could affect the microbial structure of facial skin as well as the biophysical properties of the facial skin. These findings expand our understanding of the role of skincare products on the skin environment.

Synthesis of Retinol-Loaded Lipid Nanocarrier via Vacuum Emulsification to Improve Topical Skin Delivery.

Retinol has been widely used as an anti-wrinkle active ingredient in cosmetic fields. However, the oxidation of retinol by air was one of the critical problems for application in the skincare field. In this study, Retinol-loaded lipid nanocarriers were prepared via the vacuum emulsification method to increase the stability of retinol vulnerable to air and optimized encapsulation conditions and to increase the penetration efficiency into skin. Optimizing the components of lipid nanocarriers, gradients of carbon chain C8-22 using various lipid species which made the amorphous structure and enough spaces to load retinol inside the capsules were estimated from the lower enthalpy change and peak shift in DSC analysis. The vacuum-assisted lipid nanocarriers (VLN) could help suppress oxidation, which could have advantages to increase the thermal stability of retinol. The retinol-loaded VLN (VLN-ROL) had narrow size distribution under 0.3 PDI value, under 200 nm scaled particle size, and fully negative surface charge of about -50 mV for the electrostatic repulsion to avoid aggregation phenomenon among the lipid nanoparticles. It maintained 90% or more retinol concentration after 4 weeks of storage at 25, 40 and 50 °C and kept stable. The VLN-ROL-containing cream showed improved penetration efficiency applied to porcine skins compared to the commercial retinol 10S from BASF. The total amount of retinol into the skin of VLN-ROL (0.1% of retinol) was enhanced by about 2.2-fold (2.86 ± 0.23 µg) higher than that in 0.1% of bare retinol (about 1.29 ± 0.09 µg). In addition, applied on a 3D Human skin model, the epidermal thickness and the relative percentage of dermal collagen area effectively increased compared to the control and retinol, respectively. Additionally, the level of secreted IL-1α was lower and epidermal damage was weaker than commercial product A. This retinol-loaded lipid nanocarrier could be a potentially superior material for cosmetics and biomedical research.